Charge transport and applications to the secondary batteries of lithium salt doped polyaniline

We report the results of temperature dependence of dc conductivity [δ_dc(T)], the electron paramagnetic resonance (EPR), and the thermoelectric power, as well as X-ray photoelectron spectroscopy (XPS) experiments, for polyaniline samples (PANs) doped with various Li salts such as LiPF₆, LiBF₄, LiAsF₆, LiCF₃SO₃, and LiClO₄. Similar to protonic acid doped polyaniline (PANES) samples, a quasi one dimensional variable range hopping (quasi-1D VRH) model provided the best fitting for the δ7_dc(T) of the Li salt doped PAN samples. The temperature dependence of δ_dc(T) varied with the kinds and the doping levels of the Li salts used. The temperature dependence of the thermoelectric power of PAN doped with LiPF₆ showed a metallic behavior. From the EPR experiments, x^Pauli depended on the kinds and the doping levels of the Li salts used. We present the variations of the δ_dc and the density of states as functions of the molar concentrations of the Li salts. The results of the δ_dc (RT), XPS, and EPR experiments show an insulator-metal transition with increasing molar concentration of Li salts. The results of the XPS experiment are discussed to account for the doping procedure of the systems.